0:00
introduction to sterilization
0:02
sterilization is defined as the complete
0:04
elimination of all forms of microbial
0:06
life this includes bacteria viruses
0:11
spores it's important to understand the
0:13
difference between sterilization and
0:16
disinfection sterilization completely
0:18
eliminates all microorganisms while
0:21
disinfection only reduces the number of
0:25
level sterilization is crucial across
0:28
multiple industries in healthcare it
0:30
prevents infections during surgeries and
0:33
medical procedures in laboratory
0:35
settings it ensures experimental
0:37
accuracy by eliminating contamination
0:39
and in food processing it extends shelf
0:42
life and ensures consumer
0:44
safety let's visualize the sterilization
0:47
process during sterilization all
0:50
microorganisms including resistant
0:51
bacterial spores are completely
0:55
in this course we will explore seven
0:58
major physical sterilization methods
1:00
used across different industries each
1:02
method has specific applications
1:04
advantages and limitations that we'll
1:07
explore in the following
1:10
sections moist heat sterilization is one
1:12
of the most widely used methods for
1:14
eliminating microorganisms from
1:16
equipment and materials the primary
1:19
mechanism of action is protein
1:21
dennaturation when exposed to moist heat
1:24
the proteins within microorganisms
1:26
unfold and coagulate destroying cellular
1:28
structures and enzyatic functions as
1:31
temperature rises hydrogen bonds break
1:33
tertiary structures collapse and
1:35
proteins lose their functional
1:37
configuration leading to cell
1:40
death the autoclave is the primary
1:43
equipment used for moist heat
1:44
sterilization it operates at 121° C
1:48
under 15 lb per square in of pressure
1:51
for 15 to 20 minutes inside the
1:54
autoclave saturated steam under pressure
1:57
creates an environment where water boils
1:59
at higher temperatures than normal
2:03
conditions the steam penetration process
2:05
is what makes moist heat sterilization
2:07
so effective steam easily penetrates
2:10
wrapped materials and hollow instruments
2:13
ensuring complete contact with all
2:16
surfaces moist heat sterilization is
2:18
widely used for various applications
2:21
including medical equipment laboratory
2:23
media surgical instruments and
2:27
products the advantages of moist heat
2:29
sterilization include high reliability
2:32
absence of toxic residues ability to
2:34
penetrate wrapped materials and
2:36
wellestablished protocols
2:38
however this method has limitations it's
2:41
not suitable for heat sensitive
2:43
materials cannot effectively sterilize
2:45
oils or powders requires expensive
2:47
equipment and needs trained
2:53
operators dry heat sterilization is a
2:56
method that utilizes high temperatures
2:58
in the absence of moisture to eliminate
3:00
all forms of microbial life
3:04
dry heat sterilization works through the
3:06
oxidation of cell components this
3:08
process denatures proteins disrupts cell
3:11
membranes and damages DNA and RNA
3:14
ultimately leading to cell
3:15
death when exposed to dry heat bacterial
3:22
down there are two main methods of dry
3:25
heat sterilization hot air ovens operate
3:28
at temperatures between 160 and 180° C
3:32
for 2 to four hours providing slow but
3:35
thorough sterilization incineration on
3:37
the other hand uses direct flame
3:39
exposure at temperatures exceeding 800°
3:42
C resulting in immediate destruction of
3:47
microorganisms dry heat sterilization is
3:49
particularly suitable for several types
3:51
of materials these include laboratory
3:54
glassware metal instruments powders
3:56
non-acquous substances heat stable oils
3:59
and petroleum products incineration is
4:02
commonly used for disposable items like
4:06
needles when compared to moist heat
4:08
sterilization dry heat requires higher
4:11
temperatures of 160 to 180° and longer
4:15
exposure times of 2 to 4 hours it works
4:18
through oxidation rather than protein
4:22
in contrast moist heat operates at lower
4:25
temperatures of 121 to 134° C for just
4:29
15 to 30 minutes while moist heat offers
4:32
more efficient penetration dry heat is
4:34
better suited for moisture sensitive
4:38
items dry heat sterilization has several
4:41
limitations it can potentially damage
4:43
heat sensitive materials and is a
4:45
timeconuming process when using hot air
4:48
ovens it offers poor penetration into
4:51
dense materials and consumes more energy
4:53
than moist heat sterilization
4:55
additionally dry heat is not suitable
4:57
for most plastics rubber or textile
5:00
materials due to the high temperatures
5:02
required for effective
5:04
sterilization in summary dry heat
5:07
sterilization is an effective method for
5:09
heat stable moisture sensitive items but
5:12
it requires higher temperatures and
5:14
longer exposure times compared to moist
5:23
radiation sterilization employs
5:24
different types of radiation to
5:27
microorganisms gamma rays from cobalt 60
5:30
are high energy photons that penetrate
5:32
deeply into materials electron beam uses
5:35
accelerated electrons while UV radiation
5:38
is effective for surface sterilization
5:44
ionizing radiation damages the DNA of
5:47
microorganisms through direct and
5:49
indirect mechanisms when gamma radiation
5:51
from cobalt 60 interacts with cells it
5:54
creates free radicals and directly
5:56
breaks chemical bonds in the DNA these
5:59
DNA breaks prevent microbial
6:01
reproduction and cause cell death
6:03
effectively sterilizing the material
6:08
radiation sterilization is widely used
6:11
for medical supplies including syringes
6:13
implants and surgical tools in the
6:16
pharmaceutical industry it's used for
6:18
raw materials and some finished products
6:20
for food preservation radiation extends
6:22
shelf life of spices fruits and certain
6:28
products radiation sterilization offers
6:31
several advantages and has some
6:33
limitations to consider advantages
6:35
include deep penetration ability no
6:37
temperature increase the ability to
6:39
sterilize sealed packages and no
6:41
chemical residues limitations include
6:44
potential material degradation
6:46
specialized equipment requirements high
6:48
initial costs and incompatibility with
6:54
materials for medical devices the
6:57
typical sterilization dose is 25 kg
7:00
which provides a sterility assurance
7:02
level of 10 the minus 6 various
7:05
equipment is used for radiation
7:07
sterilization including gamma
7:08
irradiation chambers using cobalt 60
7:11
electron beam accelerators x-ray
7:14
conversion systems and UV sterilization
7:18
radiation sterilization is highly
7:20
effective and widely used for terminal
7:22
sterilization of many products in
7:24
healthcare and food industries high
7:27
pressure sterilization also known as
7:29
pascalization is a non-therrmal food
7:32
preservation method that uses extremely
7:34
high pressures to inactivate
7:36
microorganisms this method applies
7:38
pressures of 400 to 800 megapascals
7:42
which is approximately 4,000 to 8,000
7:45
times atmospheric pressure
7:48
high pressure disrupts cellular
7:50
structures in microorganisms the intense
7:53
pressure disrupts cell membranes and
7:55
denatures proteins which inactivates the
8:01
microorganisms high pressure
8:03
sterilization is primarily used in food
8:05
processing for items like fruit juices
8:07
ready to eat meats and seafood products
8:12
high pressure sterilization offers
8:14
significant advantages including minimal
8:16
effect on nutritional value flavor and
8:19
appearance it eliminates the need for
8:22
chemical additives and can be performed
8:24
at room temperature however this method
8:26
has limitations the equipment is
8:28
expensive and the process is ineffective
8:31
against bacterial spores it's currently
8:33
limited to batch processing and not all
8:36
food products are suitable for this
8:40
a key limitation of high pressure
8:42
sterilization is its ineffectiveness
8:44
against bacterial spores these spores
8:47
have multiple protective layers and low
8:49
water content making them resistant to
8:54
treatment filtration is a physical
8:57
method of sterilization that separates
8:59
microorganisms from liquids and gases by
9:02
passing them through specialized
9:03
membrane filters membrane filters
9:06
typically have pore sizes ranging from 2
9:09
to 0.45 micrometers these microscopic
9:12
openings are small enough to trap
9:14
bacteria and other microorganisms when
9:17
liquids or gases pass through these
9:18
filters microorganisms like bacteria are
9:21
trapped on the filter surface while the
9:23
filtered fluid passes through however
9:27
standard filters with
9:28
0.2.45 micrometer pores cannot trap
9:31
viruses which are typically much smaller
9:35
filtration methods are widely used
9:37
across various fields particularly for
9:39
sterilizing heat sensitive materials in
9:42
pharmaceutical manufacturing filtration
9:44
sterilizes injectable solutions
9:47
biological products and culture media
9:50
laboratories use it for cell culture
9:51
media and buffer solutions while
9:54
hospitals rely on filtration for IV
9:56
fluids and water purification
9:59
filtration sterilization offers several
10:01
advantages and has some important
10:03
limitations to consider among its
10:05
advantages filtration is ideal for heat
10:07
sensitive materials leaves no chemical
10:10
residues and preserves the properties of
10:12
the filtered product however limitations
10:15
include filter clogging that requires
10:17
replacement the inability to remove
10:19
viruses with standard filters and
10:23
capacity hepa filters which stands for
10:26
high efficiency particulate air filters
10:29
are specially designed for air
10:30
filtration in critical environments
10:33
these filters can remove
10:36
99.97% of particles that are 0.3
10:39
micrometers or larger from the air
10:41
making them essential for clean rooms
10:43
operating theaters and other controlled
10:45
environments hepoiltration is critical
10:48
in pharmaceutical clean rooms operating
10:50
theaters biological safety cabinets and
10:53
industries requiring high purity air
10:55
such as aerospace and micro electronics
10:59
manufacturing sonic and ultrasonic
11:01
sterilization harnesses the power of
11:03
sound waves to destroy microorganisms
11:06
sound waves exist across a spectrum of
11:09
frequencies we can use both audible
11:11
sound ranging from 20 herz to 20 kHz as
11:20
human the key mechanism of ultrasonic
11:22
sterilization is a process called
11:30
cavitation in the low pressure regions
11:33
microscopic bubbles form as the liquid
11:35
temporarily vaporizes these bubbles
11:38
rapidly collapse when they enter high
11:40
pressure regions creating powerful shock
11:42
waves these shock waves damage cell
11:44
membranes disrupt cellular function and
11:50
microorganisms ultrasonic sterilization
11:52
systems operate within specific
11:55
parameters frequencies typically range
11:58
from 20 kHz to 2 m with higher
12:01
frequencies providing more precision but
12:03
less power power density varies from 100
12:06
to 1,000 watts per liter adjusted based
12:10
on the specific application and required
12:12
level of sterilization treatment time
12:15
can vary significantly from just seconds
12:17
to 30 minutes depending on the
12:19
microorganism type and the degree of
12:24
needed ultrasonic sterilization has
12:27
several important applications across
12:29
different industries in food processing
12:32
ultrasonic treatments can inactivate
12:34
enzymes and microorganisms while
12:35
preserving nutrients and extending shelf
12:37
life all with minimal heat
12:40
damage for medical devices ultrasonic
12:43
cleaners are particularly effective at
12:46
removing contaminants from complex
12:48
instruments reaching crevices that are
12:50
difficult to clean through other methods
12:52
in water treatment ultrasonic waves can
12:55
break down contaminants disrupt
12:57
bacterial aggregates and enhance
12:59
chemical treatments for both industrial
13:04
applications let's examine the
13:06
advantages and limitations of sonic and
13:08
ultrasonic sterilization methods the
13:10
advantages include low temperature
13:12
operation which preserves heat sensitive
13:15
materials no chemical residues ability
13:17
to penetrate complex shapes
13:20
environmental friendliness and
13:22
compatibility with other sterilization
13:23
methods however there are important
13:26
limitations to consider effectiveness
13:28
can be inconsistent making it typically
13:31
used as a supplementary rather than
13:33
standalone method it has limited
13:35
penetration in dense materials may not
13:37
eliminate all bacterial spores and the
13:45
costly solar disinfection or sodus is a
13:49
water treatment method that uses UVA
13:51
radiation and thermal effects from
13:53
sunlight to inactivate pathogenic
13:56
microorganisms the Sodus process is
13:58
straightforward first fill clear plastic
14:01
or glass bottles with water next expose
14:04
these bottles to direct sunlight for at
14:05
least 6 hours ideally on a reflective
14:08
surface during exposure UVA radiation
14:11
penetrates the water while solar heat
14:13
raises the temperature working together
14:17
pathogens at a microscopic level sodas
14:20
works through two main mechanisms uva
14:22
radiation damages the DNA and proteins
14:24
of microorganisms as exposure time
14:27
increases pathogens gradually become
14:29
inactivated the process may be slow but
14:32
after 6 hours a significant reduction in
14:34
viable microorganisms is
14:37
achieved sodus offers several
14:39
significant advantages it's low cost
14:42
simple to implement requires no
14:44
chemicals is widely accessible and
14:46
provides a sustainable solution for
14:48
water treatment however Sodus also has
14:51
important limitations it's weather
14:53
dependent has limited volume capacity
14:56
requires at least 6 hours of sunlight is
14:58
less effective on cloudy days and
15:01
doesn't work against all types of
15:03
pathogens sodus is particularly valuable
15:06
in resource limited settings it serves
15:09
rural communities where conventional
15:10
water treatment is unavailable provides
15:13
relief during humanitarian crisis and
15:15
offers a solution during emergency
15:17
situations it's important to note that
15:20
sodus is primarily a disinfection method
15:22
rather than complete sterilization it
15:25
significantly reduces microbial load but
15:27
does not eliminate all
15:29
microorganisms some pathogens
15:31
particularly certain prozzoa and
15:33
bacterial spores may show resistance to
15:37
treatment sodus can achieve up to 99.9%
15:41
reduction of certain bacteria like ecoli
15:44
salmonella and vibriocalerie however
15:47
it's less effective against some viruses
15:49
and prozzoa and is not recommended for
15:51
heavily contaminated water for best
15:53
results use clear not colored bottles
15:56
place them on reflective surfaces to
15:58
maximize exposure pre-filter turbid
16:00
water to improve light penetration and
16:03
double the exposure time on cloudy days